Composed of a lipid bilayer with proteins and carbs all with a specific function. Lipids are oriented so their polar, water- loving, hydrophyllic components are adjacent to aqueous environments. The nonpolar , water-fearing hydrocarbon chains are positioned away from water towards the center of the cell membrane. The proteins act as attachment sutes for molecules in the extracellular fluid + they form channels to transport substances in and out of cells; the position of lipids, proteins, and carbs constantly changes due to changes in cellular demands. This ever changing pattern makes it a fluid mosaic model.